Low-water alarm



Nov. 16 1926.

R. L. BADGER LOW WATER ALARM Filed April 1 1925 avwentoz W5; of fi attorney Patented Nov. 16, 1926.

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ROY L. BADGER, YOUNGSTOWN. OHIO.

LOXV-WATEB ALARM.

Application filed April 18,

One form of low water alarm heretofore used has embodied a container having an expansible fluid therein which when heated to a predetermined point is arranged to actuate a signal in one form or another. The principal objection to the use. of an expansible fluid is the liability for the fluid when gasified to escape and thereby to render the device inoperative. Another form of low water alarm has embodied the use. of an expansible element but this is open to objection on account of the large size which is usually required for practical purposes.

The principal object of the present invention is the provision of a low water alarm which may be readily attached to a boiler, yet which is compact and operates positively to indicate the we er condition in the boiler. In this connection my invention contemplates the use of a device which embodies few working parts, and which may be assembled in an expeditious manner.

In carrying out my invention 1 have shown in the drawing a section through part of a locomotive boiler with a device embodying my invention attached thereto.

In the drawing designates a roof sheet and 11 a crown sheet of a boiler which are reinforced by a stay bolt 12 in the usual manner. A tubular member 13 open at the top and closed at the bottom extends through openings in the roof and crown sheets, and is permanently secured thereto as by welding at M and 15 respectively. The tubular member 13 preferably embodies a cylindrical pipe, the outer bottom surface 16 of which is flush with the fire box side of the crown sheet. The upper surface 17 of the bottom is shown as extended above the water surface of the crown sheet, so that the level of the water in the boiler drops below the surface 17 when the extreme danger point is reached. As soon as the water drops below the level indicated by the surface 17 then the bottom of the tube is subjected almost entirely to the heat in the fire box which results in sounding the alarm.

Within the tube I provide a pyrometer or thermo-couple indicated in general at 20. The lower end of the thermo-couple is placed in engagement with the surface 17 adjacent to the bottom of the tube and is shown as being held there against by a spring 21 one end of which engages a shoulder 22 on the thermo-couple and the other end of which engages a washer 23. This 1925. Serial No. 24,107.

washer may form the inner retaining member of a stuffing box indicated at 2 L. The function of the stufiing box is to maintain the space within the tube in substantially air tight condition so as to avoid heat radiation as much as possible.

The. pyrometer may project through the stufiing box while the respective members which form the couple may be electrically connected as by leads and 26 to binding posts 27 and 28. From binding post 27, a wire 29 is shown as being connected at 30 to a recording meter 31. A return wire 33 extends from the connection 32 to binding post 28.

It is well known that a thermo-conple when subjected to heat generates an electric current, the pressure of which can be measured with a mili-voltmeter. By employing a meter such as a recording gage 31 then a permanent record of the water condition in the boiler may be maintained.

I have indicated an alarm which may he energized from a source of an electrical supply 51 whenever the circuit to the alarm is closed. To complete the alarm circuit I have shown a wire 52 which leads from wire 29 at 53 to the alarm, and I have. shown a wire 54 which leads from the alarm to the source of supply. A wire 55 then may connect the source of supply with a terminal connection 56 on the recording meter. The meter may be so arranged that whenever the indicating arm 57 reaches a predetermined point, a connection is made with the terminal 56 to complete the circuit through the source of supply and to sound the alarm. An important advantage of a low water alarm embodying my invention is the necessity for cutting only a comparatively small hole through the boiler sheet to effect the desired connection. By employing a substantially airtight chamber in which the pyrometer is mounted I reduce radiation losses to a minimum by preventing the rapid dissipation of heat due to the movement of boiling water around the casing in which the pyrometer is mounted.

I claim:

1. In combination, a. boiler having a crown sheet and a roof sheet, a casing secured to the crown sheet and extending through the roof sheet, a thermo-couple mounted within the casing, an electrical conduit connected to the thermo-couple outside the boiler, said conduit being adapted to be electrically connected in circuit with an external indicator.

2. In combination, a boiler, a casing rigidly carried thereby and having a closed bottom and an open top, a thermo-couple held in abutting engagement with the bottom of said member, means providing a substantially air tight chamber Within the casing, and electrical conduits leading from the thermo-couple outside the boiler, said conduits being adapted to be connected with an external indicator. V

3. In combination, a boiler, a tube having one end closed and the other end open, said tube being permanently connected to the boiler, a thermo-couple Withinsaid tube, said thermo-couple having a portion thereof projectiug through the open endof said tube, means for adjustably closing the end of said tube so as to provide a substantially air tight chamber within said tube, and an electrical connection leading from the thermocouple, said connection being adapted to be connected with an external indicator.

t. In combination, a boiler having an opening therein, a hollow member closed at one end and open atthe other end, and occupying said oiening, said member being united with the oiler and having aport ion thereof projecting outside the boiler, a thermocouple within said member, means for holding the ,ther no-couple in engagement with a part of said member, and means outside the boiler for closing the open end of said member so as ,to provide an air tight chamber within the member.

In combination, a boiler having a roof sheet and a crown sheet, each of said sheets having an opening therein, a tubular member extending through the openings and being united to the crown sheet, a thermocouple within said member and in abutting engagement with the closed end thereof, said thermo-couple projecting beyond the member, means associated with the member for a'djustably closing the outer endthereof, and an electrical connection associated with the ,thermo-couple outside the boiler, said connections adapted to be connected with an external ndicator,

(5. lncombination, a boiler having a roof sheet'and a crown sheet, a'tubularinember having a closed bottom and an open top, the outer surface of said bottom being substantially flush with the tire box side of the crown sheet and the inner surface of the bottom being disposed above the Water side of the crown sheet, said member being rigidly connected with said roof and crown sheets, a thermocouple in said member, said thern'io-couple being in abutting engagement with the inner surface of the bottom 'of Said member, electrical conduits leadingfroin'the thermo-cmiple outside the boiler, said cohduits being adapted to be connected with an external indicator.

7. The combination with a boiler having a crown sheet and a roof sheet, of a casing secured to'the crown sheet and standing in both the water and steam space of the boiler, a thermo-couple located within said casing in a position normally within the water space but above the safe low water level and means leading fromsaid thernio-couple through the roof sheet for controlling an external indicator.

The combination of a boiler having a crown sheet and roof sheet, a heat conducting member extending'fromthe fire box through the crown sheet, and having a recess in its upper end, a thermocouple lo cated in said recess, and an external indicator controlled by said couple.

9. The combination with a boiler having a crown sheet and a roof sheet, of a casing secured to the crown sheet and extending through the roof sheet, a thermo-couple located within said casing in a position normally within the water space but adapted to be above thesafe lowwater level, solid conducting metal extending from the fire box to the thermocouple, and ine'ans'leading from said thermocouple and extending from the casing beyond the roof sheet for controllingan external indicator.

In testimony whereof, I-hereunto aflix my signature.

nor L. mpose; 

